x,y = map(int,input().split()) n = int(input())+1 N = 1<<n X = [0]*n Y = [0]*n W = [0.0]*N X[0],Y[0] = x,y for i in range(1,n): x,y,w = input().split() X[i],Y[i] = int(x), int(y) for j in range(1<<i): W[j+(1<<i)] = W[j] + float(w) def d(i,j,w): return (abs(X[i]-X[j])+abs(Y[i]-Y[j]))/120*(w+100) INF = 1e9 dp = [[INF]*n for _ in range(N)] # 残り配達、最後の地点 dp[N-1][0] = 0.0 for mask in range(N-1,-1,-1): for i in range(n): for j in range(n): if i==j: continue if mask>>j&1 == 0: continue nmask = mask^(1<<j) dp[nmask][j] = min(dp[nmask][j],dp[mask][i] + d(i,j,W[mask]) + W[mask]-W[nmask]) print(dp[0][0])